1. Field
The following description relates generally to wireless communications, and more particularly to implementing context fetching between network nodes after inter-system handover in a wireless communication environment.
2. Background
Wireless communication systems are widely deployed to provide various types of communication content such as, for example, voice, data, and so on. Typical wireless communication systems can be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, . . . ). Examples of such multiple-access systems can include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), and/or multi-carrier wireless specifications such as evolution data optimized (EV-DO), one or more revisions thereof, etc.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple mobile devices. Each mobile device can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations can be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth. In addition, mobile devices can communicate with other mobile devices (and/or base stations with other base stations) in peer-to-peer wireless network configurations.
In a wireless communication network, a mobile device can register with a network node of a core network to establish a security relationship. A security context for the security relationship can be generated, and the security context can be retained by the mobile device and the network node. The security context can be utilized, for example, to integrity protect a message sent by the mobile device to the network node; the message can be sent over the air to a base station, and the base station can thereafter send the message to the network node of the core network. The network node can check the integrity of the received message by employing the security context. Following this example, the security context can include a key shared between the network node and the mobile device.
Moreover, the mobile device can handover between disparate types of systems. According to an example, the mobile device can establish a security relationship with a first network node of a first type of system, thereby yielding a first security context that can be retained by both the mobile device and the first network node of the first type of system. Thereafter, the mobile device can handover to a second type of system. Thus, a security relationship with a second network node of the second type of system can be established, and a second security context corresponding to this security relationship can be retained by both the mobile device and the second network node of the second type of system. Moreover, the mobile device and the first network node of the first type of system can continue to retain the first security context subsequent to the handover to the second type of system.
Further, the mobile device can again handover back to the first type of system. As part of the handover procedure, a mapped security context for the first type of system can be derived from the second security context for the second type of system. Moreover, the mobile device can send a message to a third network node included in the core network of the first type of system, where the third network node can differ from the first network node that has the first security context for the mobile device. Accordingly, the third network node can attempt to fetch the first security context from the first network node rather than causing the mobile device to reestablish the security relationship, and thus, recreating the first security context for the first type of system can be mitigated. Recreation of the first security context can be costly in terms of latency, processing, bandwidth usage, etc. due to retrieval of authentication materials (e.g., from a Home Subscriber Server (HSS), . . . ), effectuating authentication of the mobile device, and so forth. By fetching the first security context retained by the first network node instead of recreating such security context, these costs can be diminished. When employing convention techniques, however, a network node oftentimes is unable to fetch a security context from a disparate network node within a core network associated with a type of system after an inter-system handover.